1. Field of the Invention
The present invention relates generally to balloon catheters which are used for catheterizing a body cavity. More specifically, the present invention relates to a balloon catheter with an improved balloon orientation wherein the balloon is configured to decrease irritation caused by the catheter while the catheter remains in the body cavity.
2. State of the Art
There are numerous situations in which a body cavity must be catheterized to achieve some desired medical goal. Most frequently, catheterization is performed either to insert substances into or to remove substances from the body. During many of these procedures, it is necessary to keep the catheter in a relatively stable position to perform the desired insertion or removal. With the use of enteral feeding catheters (i.e. catheters which enable the administration of nutritional solutions directly into the stomach or intestines), for example, it is necessary to ensure that the catheter is not accidentally removed from the stomach or intestines. This is true both during the actual administration or removal of fluids, and the time periods in between feedings.
In order to ensure that a catheter is maintained in the proper position, it is common to use a balloon disposed near the distal (patient) end of the catheter shaft. Inflating the balloon causes the balloon to contact the anatomical structure (i.e. a duct or stomach wall) and thereby prevents the catheter from moving out of the proper position. In the case of enteral feeding, a stoma is formed leading into the stomach or intestine. A catheter is positioned to extend through the stoma, so as to form a channel into the stomach or intestines through which enteral feeding solutions may be pumped.
FIG. 1 shows a side view of a balloon catheter, generally indicated at 10, made in accordance with the prior art. The balloon catheter 10, has a head 14 disposed at a proximal end. The head 14 contains valves which regulate the flow of fluids through the balloon catheter 10. The head 14 also prevents the balloon catheter 10 from completely advancing through the stoma and into the stomach or intestine of the user.
To prevent the catheter from being pulled out of the stomach/intestinal wall, a balloon 18 is disposed along a catheter segment 22. The catheter segment 22 includes an elongate catheter shaft 26 and a stiff tip 30 which is attached to the catheter shaft at a distal end opposite the head 14. The catheter shaft 26 is typically made of a medical grade silicone. The stiff tip 30 is also typically formed of a medical grade silicone, but is usually configured to be more rigid than the catheter shaft. The stiff tip 30 assists the physician, etc., in inserting the catheter segment 22 through the stoma.
The balloon 18 is typically attached at a proximal end 18a to the catheter shaft 26 by the use of adhesive, thereby forming a proximal cuff 32. Likewise, the distal end 18b of the balloon 18 is typically adhesively attached to the stiff tip 30, thereby forming a distal cuff 34.
The balloon 18 is advantageous because it allows the catheter segment 22 to be inserted into the stoma while the balloon is uninflated. Once the catheter segment 22 is properly positioned in the stoma, a syringe (not shown) is inserted into a side port 36 of the head 14 and a fluid is injected into the balloon 18 through a lumen (not shown in FIG. 1) of the catheter. The fluid inflates the balloon so that it extends outwardly from the catheter shaft 26 and the stiff tip 30.
While the balloon 18 remains inflated, the catheter segment 22 stays properly positioned in the stoma. If the catheter segment 22 needs to be removed, the balloon 18 may be deflated so that it will not interfere with withdrawal of the catheter shaft 26 and stiff tip 30. In such a manner, the position of the balloon catheter 10 is maintained until removal is desired.
While the configuration shown in FIG. 1 works well for maintaining the balloon catheter 10 in the proper position, the balloon catheter does have disadvantages. A primary disadvantage is discomfort to the user. In order to allow insertion of the catheter segment 22, the catheter shaft 26 and especially the stiff tip 30 must be relatively firm to prevent buckling under insertion pressures. This same firmness, however, makes the distal tip 26 much more prone to irritate anatomical structures which come into contact with the stiff tip 30. This is especially true in the stomach and intestines where the opposing walls of the anatomical structures tend to collapse on each other during physical exertion, or when the cavity has little or no food. As the person moves, the stiff tip 30 repeatedly engages the adjacent anatomical structure (such as the stomach wall) and can lead to considerable irritation and discomfort for the user.
While it would be advantageous to prevent the stiff tip 30 from contacting any adjacent anatomical structures, the balloon 18 provides certain inherent limitations. The balloon 18 must have the proximal and distal cuffs, 32 and 34, to seal form the balloon when fluid is injected into the lumen in communication with the balloon. Additionally, the cuffs 32 and 34 must be of sufficient length to provide a tight and durable seal between the balloon 18 and the catheter shaft 22 which will withstand bending and flexing caused by movements of the user. Thus, several millimeters of the distal tip 26 (and potentially the distal end of the cuff) are left exposed--leaving a significant potential for irritation.
Another disadvantage with the configuration shown in FIG. 1 is that the distal cuff 34 forms a joint 34a at its distal end. The joint 34a provides an abrupt edge which has a tendency to catch on the tissue defining the stoma through which the catheter segment 22 is placed, thereby frustrating insertion of the balloon catheter 10. As the joint 34a catches on the tissue, it can cause the catheter segment to buckle and can also cause irritation.
Thus, there is a need for an improved balloon catheter having a balloon orientation which isolates the firm distal tip from internal body cavity surfaces. There is also a need for an improved balloon catheter which lacks a joint or abrupt edge along the catheter segment which can interfere with catheter placement through the stoma.